The Effects of Leptin on the Proliferation and Differentiation of Primary Chondrocytes in Vitro and Cartilage Regeneration in Vivo

Patients with cartilage damage have various discomforts, including pain, clicks, deformities, and dysfunction. Chondrocytes are a crucial component of cartilage restoration; however, their limited proliferative ability and degenerative specificity dramatically reduce their effectiveness. In the present study, the effects of leptin on chondrocyte proliferation, chondrogenic and secretion marker gene expression, and chondrocyte cartilage matrix component secretion were evaluated in vitro. The roles of the mitogen-activated protein kinase (MAPK) and protein kinase B (AKT) signaling pathways in these processes were also investigated. More importantly, a leptin sustained release system was developed using a hydrogel with calcium alginate microspheres and was transplanted into cartilage defects in rabbit femurs to analyze the effect of leptin on promoting cartilage restoration. The results showed that leptin promoted cell proliferation and chondrocyte gene expression in a dose-dependent manner, and a concentrat...